Contact for direct reception of printed circuit board



OCL 14, 1969 RUEHLEMANN Re. 26,692

CONTACT FOR DIRECT RECEPTION 0F PRINTED CIRCUIT BOARD Original FiledMarch 20. 1961 3 Sheets-Sheet 1 224 mmvrox.

232 HERBERT E. RUEHLEMANN ATTORNEYS Oct. 14, 1969 RUEHLEMANN Re. 26,692

CONTACT FOR DIRECT RECEPTION 0F PRINTED CIRCUIT BOARD Original FiledMarch 20, 1961 3 Sheets-Sheet 2 27 F163 F|6.4 FI6.5

INVENTOR. HERBERT E. RUEHLEMANN WWW ATTORNEYS Oct. 14, 1969 RUEHLEMANNRe. 26,692

CONTACT FOR DIRECT RECEPTION OF PRINTED CIRCUIT BOARD Original FiledMarch 20, 1961 5 Sheets-Sheet :5

FIGS F169 FIG-IO 224 #224 I L 222 -222 222 J INVENTOR. HERBERT E.RUEHLEMANN ATTORNEYS United States Patent Matter enclosed in heavybrackets I: appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the add tionsmade by reissue.

4 Claims ABSTRACT OF THE DISCLOSURE Species of printed-circuit card-edgewire-wrap contacts include a double cantilever nose section comprised ofa pivot arm connected at one end to a support leg and at the other endto a wiping finger having a wiping surface. The connection between thepivot arm and support leg constitutes a first pivot section comprised oflengths of said pivot arm and support leg lying substantially in asingle plane, and the connection between the pivot arm and wiping fingerconstitutes a second, pivot section with the angle between the wipingsurface of the wiping finger and the plane of the pivot arm being formedby a bend of either 90 degrees or .180 degrees.

This invention relates to a contact which may be affixed in aninsulating casing to form a connector member to make direct contact withprinted circuit conductive strips.

Contacts of this nature have been used heretofore and are known asbellows type contacts because compression thereof proceeds about atleast two pivot points to simulate the action of a bellows. The bellowsstructure enables the contact to firmly grip the printed circuit evenwhen the assembly is subjected to vibrations or wear. Another advantageof the bellows type contact is that the pressure exerted by the contacton the printed circuit is fairly constant even though the thickness ofthe particular printed circuit being employed may vary somewhat fromothers previously inserted.

Prior bellows type contacts have been so constructed as to have themetal strip bent almost a full 180 at each pivot point. Such severebending is practical only when the metal strip is relatively thin,namely, of the order of .008 inch thick. Unfortunately, however, thetail portion of the contact will be of the same thickness which is muchtoo weak to accept the automatic wrapping accomplished by automaticmachines. Such an automatic wrapping machine is a Keller Wire Wrapmachine which automatically secures the lead from an outside circuit tothe tail of a contact. When the contact tail is of thin material, itdeflects too easily when being automatically wrapped and thus theaccuracy of the tail type location is destroyed. Attempts have been madeto overcome this problem by doubling the material at the tail and bycontouring the tail in the longitudinal direction to a V shape, but thisentails even more bending and shaping. Should a much thicker material beused in forming the contact, the thickness of the material will make thebending operations at the head of the contact extremely difficult if notimpracticable.

It is accordingly an object of the present invention to form a bellowstype contact from a relatively thick strip of material.

A further object of this invention is to form a bellows type contactwherein at least one of the two or more pivot points constituting thebellows is formed purely by a Stamping operation and there is no bendingwhatsoever in the formation of the particular pivot point.

Yet another object of this invention is to provide a bellows typecontact wherein at least one of the pivot points lies in the same planeas the contact elements about which the pivoting action occurs.

The foregoing, as well as other objects of this invention, are achievedby providing a bellows type contact which comprises basically a headsection and a tail Section, the head section including a support leg anda pivot arm which generally are in the same plane and which were formedby a simple stamping operation. The pivot arm terminates in a wipingfinger which makes the actual contact with the printed circuitconductive strip. The wiping finger was simultaneously stamped from themetal stock with the stamping of the pivot arm and the support leg.However, in several embodiments of the invention, the wiping finger isbent either at right angles or for a full with respect to the pivot armand support leg.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same be comes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings whrein:

FIG. 1 is a perspective view of a contact constituting a firstembodiment of the present invention;

FIG. 2 is a perspective view of a plurality of contacts of FIG. Imounted in spaced opposing relationship in an insulating casing;

FIG. 3 is a sectional view taken along the lines 3-3 of FIG. 2;

FIG. 4 is a side elevational view of the contact of FIG. 1 taken fromthe side away from the wiping finger;

FIG. 5 is a view similar to FIG. 4 but taken from the side closest tothe wiping finger;

FIG. 6 is a sectional view taken along the lines 66 of FIG. 1;

FIG. 7 is a perspective view of a second embodiment of the presentinvention;

FIG. 8 is a side elevational view of the device of FIG. 7;

FIG. 9 is an elevational view of the device of FIG. 7 taken from theside away from the wiping finger;

FIG. 10 is a view similar to FIG. 9 but is taken from the side towardthe wiping finger;

FIG. 11 is a view taken along the lines 11-11 of FIG. 7;

FIG. 12 is a perspective view of a contact constituting a thirdembodiment of the present invention;

FIG. 13 is a sectional view taken through the contact of FIG. 12;

FIG. 14 is a view similar to FIG. 12 but showing two contact headssimilar to the contact head of FIG. 12 mounted on a common base fromwhich two contact tails extend whereby the contact heads are located inthe same electrical circuit;

FIG. 15 is a sectional view of the device of FIG. 14 mounted in aninsulating casing;

FIG. 16 is a side elevational view of the contact of FIG. 14;

FIG. 17 is a top plan view of the contact of FIG. 14:

FIG. 18 is a front elevational view of a contact similar to that of FIG.14 but wherein one contact tail has been eliminated;

FIG. 19 is a perspective view of a contact constituting a fourthembodiment of the present invention:

FIG. 20 is a perspective view similar to FIG. 19 but wherein the entirecontact lies in a single plane; and

FIG. 21 is a view similar to FIG. 19 but wherein the wiping finger hasbeen contoured and ofiset from the pivot arm.

Referring now in greater detail to the various figures of the drawingswherein similar reference characters refer to similar parts. A contactfor direct reception of printed circuit board constructed of highlyconductive material constituting a first embodiment of the presentinvention is generally shown at in FIG. 1 and comprises basically awiping finger 12 connected to a pivot arm 14 by means of a 180 bend 16with the pivot 14 merging at its upper end with supporting leg 18 lyingin the same plane at the junction point. It is to be noted that the 180bend 16 constitutes a first pivot point and the second pivot point 20 isto be found at the merger of pivot arm 14 and support 18.

The wiping finger 12 as shown in FIG. 2 will make mechanical andelectrical contact with the conductive members of a printed circuitboard inserted thereagainst. The wiping finger 12 is bent in a convexmanner so as to approach a complementary wiping finger as Shown in FIG.2 of the drawing, thereby enhancing the resiliency of the contacts. Ahorizontally extending shoulder 22 is optionally provided at the lowerfoot of the support leg to enhance seating of the contact in insulatingcasing 24. The contact 10 further includes a tail 27 to which anexternal circuit may be secured. This tail is of a thickness towithstand the forces created by the automatic wrapping machines. Asshown in FIGS. 1 and 3, the pivot arm 14 is displaced slightly forwardof the support leg 18 to further enhance the resiliency of contact 10.It is to be noted that the upper end of wiping finger 12 terminates in alateral tab 26 which will abut against inner walls 28 of casing 24 tolimit the expansibility of a wiping finger as urged by an insertedprinted circuit. It is to be noted that the shoulder 22 functions toseat the contact in the insulating casing and may be dispensed with ifso desired.

As shown in FIGS. 2 and 3, a pair of contacts 10 may be spaced acrossfrom each other to receive a printed circuit member having conductors onboth sides thereof. It is thus seen that a bellows type contact isprovided wherein one of the two pivot points is formed merely bystamping and need not be bent in order to perform its function. Hence, agreat labor saving is effected and, at the same time, a tail of adequatestrength is provided.

The contact shown in FIGS. 7 to 11 constitutes a second embodiment ofthe present invention. As shown in FIG. 7, contact 50 is generallysimilar to contact 10 of FIGS. 1 to 6 and includes a wiping finger 52, apivot arm 54 secured to the wiping finger 52 by a 180 bend 56. The pivotarm 54 merges into support leg 58 to establish a second pivot point 60.It is to be noted that the wiping finger 52 is centrally slit at 62 toenhance the resiliency of the contact. It is further to be noted thatthe pivot arm 54 as indicated in FIG. 8 extends slightly forwardly ofsupport leg 58. Likewise, the 180 bend 56 is positioned forwardly of thesupport leg 58.

Referring again to FIG. 7, the support leg 58 terminates in a shoulder64 which extends in a vertical direction instead of horizontally as isthe shoulder 22. Fingers 68 and 70 project from contact tail 66 to aidin its securement to an insulating casing. It is to be further notedthat upper edges of the wiping fingers 52 terminate in lateral tabs 72similar to tabs 26.

A third embodiment of the present invention is shown in FIGS. 12 to 18.This embodiment differs from the first two forms basically in the factthat the wiping finger lies at right angles to the pivot arm. As shownin FIG. 12, the contact 100 basically comprises a wiping finger 112merging into a pivot arm 114 at right angle bend 116. The pivot armmerges at its upper end with support leg 118 which lies in the sameplane as the pivot arm. Thus, pivoting occurs about right angle bend 116and also at point 120 which marks the merger of pivot arm 114 andsupport leg 118. As shown in FIG. 12 a shoulder portion below thesupport leg is absent but may be provided if desired. Hence, the contact100 lacks a shoulder such as shoulder 22 of FIG. 1 or shoulder 64 4 ofFIG. 7. The contact terminates in a tail 122 including afiixing finger124. It is to be noted that the wiping finger 112 includes a centralslit and is shaped convexly in an outward direction to enhanceresiliency. Tabs 128 are provided on the contact and function similar totabs 26 and tabs 72 of FIGS. 1 and 7 respectively.

The contact 200 of FIG. 14 is generally similar to that of FIG. 12 butcomprises a pair of opposed wiping fingers 212 which eventually mergeinto a common base 213 from which tails extend. Hence, it follows thatthe wiping fingers 212 are in the same electrical circuit whereas a pairof opposed wiping fingers 12 of FIG. 2 were electrically insulated fromeach other. The configuration of FIG. 14 is made possible because thewiping fingers lie at right angles to the pivot arm 214 and thus canoppose each other.

As shown in FIG. 14, the pivot arm 214 is displaced slightly outwardlyfrom the support leg 218. This is optional and can be dispensed withdepending upon the particular need.

Contact 200 further comprises right angle bend 216 and there is alsopresent second pivot point 220 at the juncture of pivot arm 214 andsupport leg 218. A pair of tails 222 extend from the common base 213 andinclude affixing fingers 224. The wiping arms 212 further include acentral slit 226 and tabs 228. It is further to be observed from FlG. 14that the displacement of pivot arm 214 in an outward direction isoptional and can be dispensed with as indicated in FIG. 15. FIG. 16generally shows the contact of FIG. 14 in side elevation.

The contact of FIG. 18 is generally similar to the contact of FIG. 14;however, one of the pairs of the contact tails 222 has been eliminatedand thus there remains a single contact tail 232. From an electricalstandpoint, the contact of FIG. 18 is identical to the contact of FIG.14.

The contacts of FIGS. 19 to 21 dilfer from all contacts previouslydiscussed in that both pivot points may lie in the same plane as thewiping finger, pivot arm and support leg. Hence, in the contact of FIG.19, the contact 300 generally comprises a wiping finger 312, a pivot arm314, a support leg 316 and a tail 318. The juncture 320 between wipingfinger 312 and pivot arm 314 is in the same plane as the finger and thearm. Similarly, the second pivot point 322 at the juncture of pivot arm314 and support leg 316 may lie in the same plane as the arm and the legas indicated in FIG. 20 or it may be alter.- natively displaced as shownin FIG. 19. Also, the wiping finger 312 may be bent at right angles asin phantom in FIG. 19 to enhance resiliency in a manner similar to FIG.12. Optionally, the wiping arm 312 may be bent into a convexconfiguration as shown in FIG. 21. Pressure from the inserted printedcircuit and against the wiping finger is in the direction of arrow 324of FIGS. 19 and 20. i

It is therefore seen that the contact of the present invention exerts abellows type action on the conductive strip of an inserted printedcircuit. However, at least one of the two pivot points for the bellowsaction is formed solely by a stamping action. In other words, the pivotarms lie substantially in a single plane.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed as the invention is:

1. A contact for direct reception of a printed circuit board havingprinted means thereon, said contact being stamped from a relativelyrigid fiat conductive strip, said contact comprising a head section anda tail section, said head section including at least one pivot armhaving a supporting leg extending from one end thereof and a resilientwiping finger extending from the other end thereof, the juncture of saidsupporting leg and pivot arm constituting a first pivot sectioncomprised of lengths of said supporting leg and pivot arm lyingsubstantially in a first plane and the juncture of said pivot arm andresilient wiping finger constituting a second pivot section comprised of[a] substantially [180 degree] at least a 90 degree bend, [saidsupporting leg lying in said first plane with a substantial length ofsaid pivot arm being inclined away from said first plane and displacedtoward said wiping finger in extending from said first pivot section tosaid second pivot section, said wiping arm being bowed out away fromsaid pivot arm,] said wiping arm making electrical and resilientmechanical contact with at least one printed means of said printedcircuit board, said resilient mechanical contact occurring with flexingof said wiping finger about said second pivot section and displacementof said pivot arm about said first pivot section.

2. The invention of claim 1 wherein said tail section is formed fromsaid strip with said tail section having the same thickness as saidstrip, said tail section thereby being automatically sufiiciently rigidto withstand wrapping pressures of automatic wire wrapping machines.

3. The invention of claim 1 wherein a plurality of said contact elementsare affixed to an insulating casing whereby the wiping fingers of thecontacts are disposed in pposed parallel rows.

4. The invention of claim 1 wherein said wiping arm has a wiping surfacefor making electrical and resilient mechanical Contact with at least oneprinted means of said printed circuit board, said wiping surface beingperpendioular to said first plane.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original 5 patent.

UNITED STATES PATENTS 911,032 2/1909 Dow 339-257 1,142,479 6/1915 Beck339-257 1,602,370 10/1926 Avery 33933 10 1,875,179 8/1932 Prouty 339--572,154,302 4/1939 Clement 339258 2,575,161 11/1951 Deakin 339-2582,648,356 8/1953 Beaulieu et al. 339276 2,713,673 7/1955 Batcheller339258 15 2,832,013 4/1958 Pederson et al. 339 17 2,875,425 2/1959Gilbert 339l76 2,911,612 11/1959 Jackson et al 339-17 X 2,935,725 5/1960Fox 33917 X 2,937,357 5/1960 Kennedy 339-47 20 3,007,132 10/1961Anderson 339 s x 3,047,831 7/1962 Majewski 339-258 X 3,087,136 4/1963Peterson et a1. 339-276 X 3,133,780 5/1964 Dean 339258 25 FOREIGNPATENTS 496,868 12/1938 Great Britain. 611,497 10/1948 Great Britain.730,762 5/1955 Great Britain. 580,734 8/1958 Italy.

RICHARD E. MOORE, Primary Examiner

